Antarctic Auroral Imaging
Frey, H. et al. (2008) "Antarctic Auroral Imaging" U.S. Antarctic Program (USAP) Data Center. doi: https://doi.org/10.15784/600070.
AMD - DIF Record(s)
Auroral protons are not energized by electric fields directly above the auroral atmosphere and therefore they are a much better diagnostic of processes deep in the magnetosphere. It has been shown from measurements from space by the IMAGE spacecraft that the dayside hydrogen emission is directly related to dayside reconnection processes. A four channel all-sky images had been operating at South Pole during 2004-2007 to observe auroral features in specific wavelengths channels that allowed a quantitative investigation of proton aurora. This was accomplished by measuring the Hydrogen Balmer beta line at 486.1 nm and by monitoring another wavelength band for subtracting non proton produced background emissions. South Pole allows these measurements because of the 24 hour darkness and favorable conditions even on the dayside. To increase the scientific return it was also attempted to measure the Doppler shift of the hydrogen emissions because that provides diagnostics regarding the energy of the protons. Thus the proton camera measured 3 wavelength bands simultaneously in the vicinity of the Balmer beta line to provide the line intensity near zero Doppler shift, at a substantial Doppler shift and a third channel for background. The 4-channel all-sky camera at South Pole was modified in 2008 in order to observe several types of auroras, and to distinguish the cusp reconnection aurora from the normal plasma sheet precipitation. The camera simultaneously operates in four wavelength regions that allow a distinction between auroras that are created by higher energy electrons (greater than 1 keV) and those created by low energy (less than 500 eV) precipitation. The cusp is the location where plasma enters the magnetosphere through the process of magnetic reconnection. This reconnection occurs where the Interplanetary Magnetic Field (IMF) and the terrestrial magnetic field are oriented in opposite directions. The data are represented as keograms (geomagnetic north-south slices through the time series of images) for the four different wavelengths. The top of the keogram points to the magnetic south pole. The time series allows a very quick assessment about the presence of aurora, motion, intensity, and brightness differences in the four simultaneously registered channels.
USAP-DC (current) - LDEO-LEGACY (original)